Paper-Based Bacterial Lysis Enables Sample-to-Answer Home-based DNA Testing

Nucleic acid amplification testing (NAAT) is the gold standard for infectious disease diagnostics. Currently NAATs are mainly limited to centralized laboratories, while paper-based antigen tests are used for rapid home-based diagnostics. DNA extraction, the initial sample preparation step in NAATs, remains a bottleneck that hinders its development toward home-based kits. This step requires the use of compounds detrimental to the enzymes in downstream DNA amplification. Here, this work overcomes this bottleneck by immobilizing the enzyme achromopeptidase (ACP) on nitrocellulose, to both store and enable the separation of the enzymes from the other steps. This work provides proof-of-concept that immobilized ACP is effective at lysis and release of amplifiable DNA from gram-positive Staphylococcus epidermidis and enables the use of the lysate directly for DNA amplification, without the need for heat deactivation of the enzyme. This sample preparation method requires only incubation at 37 degrees C and mild agitation, which allows to implement it with fully disposable and affordable equipment. Consequently, this work enables to combine the paper-based DNA extraction method with the isothermal recombinase polymerase amplification (RPA) followed by lateral flow detection to demonstrate a sample-to-answer NAAT packaged as an instrument free self-test kit expanding the capabilities of home-testing beyond antigen tests.